$ git clone -n https://src.fedoraproject.org/rpms/nettle.git /var/lib/mock/f40-build-2242945-53669/root/chroot_tmpdir/scmroot/nettle
Cloning into '/var/lib/mock/f40-build-2242945-53669/root/chroot_tmpdir/scmroot/nettle'...
$ git fetch origin a4b8c02bfbc6a3d913ef7227e2336d0ddd52e0e6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nettle
 * [new ref]         a4b8c02bfbc6a3d913ef7227e2336d0ddd52e0e6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a4b8c02 Migrate License field to SPDX license identifier